The rate of the painful skin condition shingles appears to be rising in at least some parts of the United States, leading many to wonder why.

Although shingles is related to chickenpox — the varicella zoster virus causes both — experts say the rise in shingles is not linked with the use of the chickenpox vaccine.

In fact, children who receive a chickenpox vaccination have a much lower risk of getting shingles later in life than those who are not immunized, said Dr. William Schaffner, doctor of preventative medicine at Vanderbilt University Medical Center in Nashville, Tennessee, and a leading infectious disease expert.